package com.lagou.edu.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.util.ArrayList;
import java.util.List;

/**
 * @author lyj
 * @Title: BlackListFilter
 * @ProjectName lagou-parent
 * @Description: TODO
 * @date 2021/1/2 2:19
 */

@Slf4j
@Component //让容器扫描到，等同于注册
public class BlackListFilter implements GlobalFilter, Ordered {


    private static List<String> blackList=new ArrayList<>();
    static {
        blackList.add("0:0:0:0:0:0:0:1");//模拟本机地址
    }

    /**
     * 过滤器核⼼⽅法
     * @param exchange 封装了request和response对象的上下⽂
     * @param chain ⽹关过滤器链（包含全局过滤器和单路由过滤器）
     * @return
     */
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        // 思路：获取客户端ip，判断是否在⿊名单中，在的话就拒绝访问，不在的话就放⾏
          // 从上下⽂中取出request和response对象
        ServerHttpRequest request = exchange.getRequest();
        ServerHttpResponse response = exchange.getResponse();

// 从request对象中获取客户端ip
        String clientIp = request.getRemoteAddress().getHostString();
        // 拿着clientIp去⿊名单中查询，存在的话就拒绝访问
        if(blackList.contains(clientIp)){
            //// 拒绝访问，返回
            response.setStatusCode(HttpStatus.UNAUTHORIZED);
            log.debug("------>Ip："+clientIp+" 在黑名单中，被拒绝访问！");
            String data="Request be denied!!";
            DataBuffer wrap = response.bufferFactory().wrap(data.getBytes());
            return response.writeWith(Mono.just(wrap));
        }

        // 合法请求，放⾏，执⾏后续的过滤器
        return chain.filter(exchange);
    }

    /**
     * 返回值表示当前过滤器的顺序(优先级)，数值越⼩，优先级越⾼
     * @return
     */
    @Override
    public int getOrder() {
        return 0;
    }
}
